Elsevier

American Heart Journal

Volume 144, Issue 3, September 2002, Pages 456-462
American Heart Journal

Clinical Investigations: Acute Ischemic Heart Disease
How long is too long? Association of time delay to successful reperfusion and ventricular function outcome in acute myocardial infarction: The case for thrombolytic therapy before planned angioplasty for acute myocardial infarction,☆☆,

https://doi.org/10.1067/mhj.2002.124868Get rights and content

Abstract

Objectives The purpose of this study was to quantify the effect of time delays to reperfusion on ventricular function after myocardial infarction. This allows one to identify a group of patients in whom a strategy using antecedent pharmacologic reperfusion therapy before planned direct angioplasty may offer significant benefit. Background Direct angioplasty for myocardial infarction is associated with a high rate of successful reperfusion compared with pharmacologic reperfusion. However, there is an inherent time delay to treatment with angioplasty compared with pharmacologic therapy. There currently are insufficient data to determine the consequences of incremental time delays to reperfusion on ventricular function. Methods We determined, by logistic regression analysis, the probability of observing a decrement in postmyocardial infarction ventricular function as a function of incremental time delays to reperfusion. Results Time delays of 30, 60, 90, or 120 minutes to reperfusion increased the likelihood of a worse ventricular function outcome by 1.1-, 1.3-, 1.5-, and 1.7-fold, respectively (P <.02). The upper 95% confidence limits around these odds ratios are as high as 1.3 or 2.7 for 30- and 120-minute delays, respectively. Time from symptom onset to patency remained a significant determinant of ventricular function after adjustment for clinical and procedural factors. Conclusions Delay in time to reperfusion, measured in minutes, results in significant loss of ventricular function after myocardial infarction. Interventional strategies designed for treatment of myocardial infarction when “door-to-balloon” time is expected to exceed 60 minutes should strongly consider incorporation of pharmacologic reperfusion therapy into the therapeutic paradigm. (Am Heart J 2002;144:456-62.)

Section snippets

Patient population

PACT was a multicenter, randomized, double-blind, placebo-controlled study in patients with an AMI that has been previously described in detail.16 Briefly, patient inclusion criteria included ischemic symptoms for ≥30 minutes, ST-segment elevation of ≥0.1 mV in ≥2 limb leads or ≥0.2 mV in ≥2 contiguous precordial leads, and MI symptoms for ≤6 hours. Patients were to have angiography as soon as possible after study drug (placebo vs 50-mg TPA) intravenous bolus administration. On arrival in the

Results

The baseline clinical and coronary angiographic characteristics of patients in the early and late reperfusion groups are described in Table I.

. Baseline characteristics of “early” and “late” reperfusion groups

Empty Cell“Early reperfusion”“Late reperfusion”P
Empty Cell(n = 37)(n = 241)Empty Cell
Age56 (48, 64)57 (48, 65).9
Male7684.2
Diabetes1412.6
Hypertension4336.3
History of smoking7172.9
Hypercholesterolemia4936.06
History of angina4133.2
History of MI229.02
History of CHF1.60.05
Anterior MI2435.2
Multivessel CAD6749.01

Values

Discussion

The association of shortened times from symptom onset to treatment and mortality reduction in the setting of AMI has been demonstrated in multiple large clinical trials.1, 2, 3 This phenomenon was also demonstrated by the Myocardial Infarction Triage and Intervention Trial (MITIT) investigators4 and by Milavetz et al,6 with time to treatment expressed as a dichotomous variable (≤70 min vs >70 min and ≤2 h vs >2 h, respectively). The results of the present study confirm and extend these previous

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  • Cited by (28)

    • New insights in the pathophysiology of acute myocardial infarction detectable by a contemporary troponin assay

      2013, Clinical Biochemistry
      Citation Excerpt :

      In particular, we have emphasized the relevance to report the effect of the time from symptom onset (time from ED presentation added of pre-hospital delay) on marker release. In fact, in these patients a wide body of literature has shown that the length of pre-hospital delay strongly affects morbidity and mortality rates and it is equally associated with successful reperfusion [16,21,22]. In addition, international guidelines recommend that reperfusion therapy should be performed within 90 min after the onset of symptoms [23].

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    Supported by a combined grant from Boehringer-Ingelheim, GmbH, Ingleheim, Germany, Boston Scientific, Natick, Mass, and Genentech, Inc, South San Francisco, Calif.

    ☆☆

    Reprint requests: Conor F. Lundergan, MD, The Cardiovascular Research Institute, The George Washington University, 2150 Pennsylvania Ave NW, Suite 4-417, Washington, DC 20037.

    E-mail: [email protected]

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